# Yoyo CAD & Prototyping Adventures **URL:** https://forums.yoyoexpert.com/t/yoyo-cad-prototyping-adventures/291547 **Category:** Yo-Yo Mods and Maintenance **Created:** [August 7, 2018, 3:40pm UTC](https://forums.yoyoexpert.com/t/yoyo-cad-prototyping-adventures/291547 "2018-08-07T15:40:59Z") **Posts on this page:** 1 **Showing post:** 275
### Author: ![MarkD](https://sea1.discourse-cdn.com/flex015/user_avatar/forums.yoyoexpert.com/markd/32/40845_2.png) [@MarkD](https://forums.yoyoexpert.com/u/MarkD) #### Post date: [April 6, 2019, 7:47pm UTC](https://forums.yoyoexpert.com/t/yoyo-cad-prototyping-adventures/291547/275 "2019-04-06T19:47:49Z")
Thanks for the rim weight/moment of inertia tutorial! I like your drawings. The moment you highlighted is actually around a different axis. Ixx is the one you want, which goes through the axle. 13,880 g mm^2 sounds pretty nice for the half and it matches my intuition for the design & the rim weight quotient you calculated (which also looks correct). > [@Mark\_Leithead](#): > > Would be cool if there were some stats on Mass of Inertias of some common throws, or if even a scale gradient exists for Mass of Inertia as for Center of Mass/Radius as shown below. [The Diffraction](https://forums.yoyoexpert.com/t/mk-1-yoyos/294446) has a moment of 14,360 and a rim weight quotient of 57.9%. The total mass is about 64.35g assembled (depends on pads/bearing used with a 8mm steel axle). It turned out really good (in my opinion) in terms of stability/etc. Throwcafe published some of the technical specs of the boba on their blog. Here’s what they said: > **The technical stuff** > > Each half has a moment of inertia of 14870 g mm^2 and weighs about 31g, for a total yoyo weight of just under 64g. In comparison, the Cappuccino’s halves weigh about 30g and a moment of 13700 g mm^2. > > An organic shape lets you put more weight where you want on the yoyo, and here it’s mostly rim weight. While the Cappuccino’s light weight and decent stability make it a speed demon, the Boba is a bit slower, more stable, and fun as an everyday throw. --- _[View the full topic](https://forums.yoyoexpert.com/t/yoyo-cad-prototyping-adventures/291547)._